One of the goals of our proposed research will be the elucidation of the mechanism of membrane transport of melibiose. We intend to study the cation requirement for a variety of transport substrates for this carrier. It is proposed to induce active transport of various substrates by setting up artificial cation gradients across the membrane of energy depleted cells. This system will be compared and contrasted with that of galactose transport system of E. coli. A second project will involve continued study of the control of lactose metabolism in Klebsiella aerogenes. Specifically, we intend to insert into Klebsiella F factors or plasmids which contain the lac operon derived from E coli. Various diploid strains will be studied for their lactose expression.